大直径超长灌注桩承载特性研究  

Study on bearing characteristics of large-diameter super-long grouted piles

作　　者：王学峰 李翱翔 史国良 岳春强 张鹏 Wang Xuefeng;Li Aoxiang;Shi Guoliang;Yue Chunqiang;Zhang Peng(China Construction Sixth Engineering Bureau CORP.,Ltd.,Tianjin 300000,China)

机构地区：[1]中国建筑第六工程局有限公司,天津300000

出　　处：《山西建筑》2025年第4期76-81,共6页Shanxi Architecture

基　　金：中国建筑股份有限公司科研课题(课题编号:CSCEC-2022-Z-25);中国建筑第六工程局有限公司科研课题(课题编号:CSCEC6B-2021-Z-5)。

摘　　要：为明确黄河中下游地区粉土、粉细砂地层中长大桩基承载特性及荷载传递机理,依托实际工程,结合室内土工试验、现场原位测试和数值模拟手段开展了系统性研究。采用自制的大型直剪仪开展了不同含水率条件下粉土-混凝土界面直剪试验,设计拉压锚法加载反力装置实现了桥梁钻孔灌注桩36000 kN大吨位加载,基于直剪试验和静载试验结果,运用ABAQUS试算拟合土体与界面参数,进一步研究了基桩水平承载能力。结果表明:粉土-混凝土界面剪切强度随粉土含水量的增大而减小,粉土含水量的增加会显著减弱土体与混凝土结构界面的剪切作用。粉土-混凝土界面剪切强度包络线基本符合摩尔库仑强度理论,土体含水量与界面的黏聚力和摩擦角呈负相关变化规律。在建立的桩土竖向静载试验模型与原位测试数据吻合性良好的前提下,开展桩基水平承载力数值模拟,发现所得结果与设计方案基本相当,满足规范要求,文中相关结论可为相关工程设计提供借鉴。In order to clarify the bearing characteristics and load transfer mechanism of long pile foundations in chalky soil and fine sand strata in the middle and lower reaches of the Yellow River,a systematic study was carried out by combining indoor geotechnical tests,field in-situ tests and numerical simulations relying on actual projects.A self-made large-scale straight shear instrument was used to carry out the straight shear test of chalk-concrete interface under different water content conditions,and a large tonnage loading device of 36000 kN was designed for bridge bored piles.Based on the results of the straight shear test and static loading test,the horizontal bearing capacity of foundation piles was further investigated by using the ABAQUS trial calculation to fit the parameters of the soil body and the interface.The results show that the shear strength of the silt-concrete interface decreases with the increase of silt water content,and the increase of silt water content will significantly weaken the shear effect at the interface between soil and concrete structure.The shear strength envelope of chalk-concrete interface basically conforms to the theory of Moore’s Coulomb strength,and the water content of the soil body is negatively correlated with the cohesion and friction angle of the interface.On the premise that the established pile-soil vertical static load test model and the in-situ test data are in good agreement,the numerical simulation of the horizontal bearing capacity of foundation pile is carried out,and it is found that the obtained results are basically comparable with the design scheme,which meets the specification requirements.The relevant conclusions of this paper can provide reference for related engineering design.

关 键 词：钻孔灌注桩 大型直剪试验 静载试验 数值模拟 

分 类 号：TU473.14[建筑科学—结构工程]